Answer:
1. 208
2. 82
3. Pb
Step-by-step explanation:
²¹²₈₄Po —> ⁴₂He + ᴬZX
1. Determination of mass number A of the new atom.
212 = 4 + A
Collect like terms
212 – 4 = A
208 = A
A = 208
Thus, the mass number is 208
2. Determination of the atomic number Z of the new atom.
84 = 2 + Z
Collect like terms
84 – 2 = Z
82 = Z
Z = 82
Thus, the atomic number is 82.
3. Determination of the symbol of the new atom.
ᴬZX => ²⁰⁸₈₂X
The atomic number of the new atom is 82. Comparing the atomic number of the new atom to those in the periodic table, the new atom is lead with symbol Pb.
Thus,
²⁰⁸₈₂X => ²⁰⁸₈₂Pb
Therefore, the symbol of the new atom is Pb.